34 D8. Structural Geology and Tectonics (Posters)

Friday, 8 April 2022
8:00 AM - 12:00 PM
Junior Ballroom B

MAGNETIC ANOMALY PATTERNS AND VOLCANO-TECTONIC FEATURES ASSOCIATED WITH GEOTHERMAL PROSPECT AREAS IN THE ZIWAY-SHALA LAKES BASIN, CENTRAL MAIN ETHIOPIAN RIFT

Paper number: 34-1
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

The Ziway-Shala Lakes Basin is a structural depression within the central Main Ethiopian Rift and contains Cenozoic volcanism, faulting and sedimentation. Within this region, the Aluto-Langano volcanic complex is currently being exploited for geothermal power production. In contrast to previous geophysical studies, recent magnetotelluric (MT) investigations reveal the nonexistence of a heat source beneath the Aluto-Langano geothermal field. Instead, the MT study revealed a low resistivity region to the northwest of Aluto beneath the Silti Debre Zeyet Fault Zone (SDFZ) which may be the magmatic heat source. To aid in determining the volcano-tectonic features within the Basin magnetic data were analyzed. The analysis included creating a differentially reduced to the pole total magnetic field anomaly map and then applying upward continuation, power spectral analysis, 2D-Werner Deconvolution, 2D forward modeling, first vertical derivative and tilt derivative filters. Interpretation of the anomaly maps and the depth analyzes suggests the existence of a heat conduction path is structurally controlled along a trend from the Aluto-Langano geothermal field to the SDFZ and occurring between depths 1.5 km and 3 km. Additionally, most of the magnetic lineaments are oriented in the direction of pre-existing Mesozoic structures and in the direction of thermally altered structures.

Geological Society of America Abstracts with Programs. Vol. 54, No. 4

doi: 10.1130/abs/2022NC-373501

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